Apparatus for gas plating continuous lengths of material



P. PAWLYK March 19, 1957 APPARATUS FOR GAS PLATING CONTINUOUS LENGTHS OF MATERIAL Original Filed Oct. 8. 1951 iii lmhTum INVENTOR PETER PAWLYK BYT" United States Patent APPARATUS FOR GAS PLATING CONTINUOUS LENGTHS OF MATERIAL Peter Pawlyk, Dayton, Ohio, assignor-to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation of Ohio Original application October 8 1951 Serial No. 250,307. Divided and this applicatiori Novdmber 3, 1953, Serial No. 390,961

2 Claims. (Cl. 118-49) This invention relates to the treatment of substantially continuous lengths of electrically non-conductive materials to deposit metallic films on the surface thereof, and to the product produced by such treatment.

This application is a division of Peter Pawlyk application, Serial No. 250,307, filed October 8, 1951, and assigned to the same assignee as the present invention.

This application is related to co-pending applications, Serial Nos. 250,301, now Patent No. 2,700,365; 250,302, now Patent No. 2,704,727; 250,303, now Patent No. 2,694,651; 250,304, now Patent No. 2,685,532; 250,305, now Patent No. 2,704,728 and 250,306, now Patent No. 2,729,190, all filed October 8, 1951, and all by the same inventor as the present application.

This invention contemplates the provision of an apparatus for the deposition of metal from gaseous metalbearing compounds onto electrically non-conductive materials in which the conditions of operation vital to the attainment of a pure metallic coating are readily controlled.

'A particularly important feature of the invention is that it may be practiced to gas plate with most metal-bearing compounds at pressures which are substantially atmospheric, it being only necessary to give sufficient velocity to the moving gases to procure their passage over the material to be plated.

The invention also contemplates the provision of, apparatus for efiecting continuous thermal decomposition of the metal-bearing gases in contact with a heated electrically non-conductive material to insure the securing of fine metal coatings. To effect this the apparatus is arranged in such manner that pressures slightly above ably include copper acetyl-acetonate, chromium carbonyl and nickel carbonyl. While I prefer to use carbon dioxide as the carrier gas with such metal-bearing compounds, and the detailed information hereinafter will refer particularly to the use of carbon dioxide, other insert gases, such as nitrogen, hydrogen, argon and helium,

are equally suited and where employed only minor ad-- justments in the apparatus of invention will be required,

as will be understood by those skilled in the art.

- The temperature of the electrical insulating material when contacted by the plating gases is an important consideration in the practice of the invention as it is the heat of the insulating material which effects the decomposition of the metal-bearing compound. The temperature of the insulating material is then to some extent related to the gaseous metal-bearing compound and must be higher than the temperature at which decomposition of the metal-bearing gaseous compound is initiated, but may not be so high that the plating atmosphere will be heated to such an extent that premature decomposition takes place. For example, poor deposits will result if the metal-bearing compound decomposes at a distance from the surface of the insulating material.

The temperature of the insulating material is also limited by the inherent characteristics of the material and must not be so high that the material may be affected thereby. This last factor will not in general be unduly terials are such that they may be readily heated beyond the temperature at which most plating gases decompose.

In any event I prefer to preheat the insulating material in a preheating system to such a temperature as to insure and below atmospheric may be attained as desired by Such products find utility in the electrical arts, as in electrical condenser apparatus where conductivity and high resistance to temperature are prerequisites.

The objects of the invention are achieved by passing from a constant temperature system a heated plating gas, comprised of a metal-bearing compound and a carrier, across the surface of heated insulated material moving in a plating chamber from a preheating system wherein the material is heated in two steps to avoid thermal shock. The hot vapors of metal-bearing compound decompose, depositing metal on the heated insulating material when contact is made therebetween. Preferably, to secure uniformity of plating, the plating gas is first passed across the material in one direction and across the material in an opposite direction without intermediate cooling.

Metal-bearing compounds useful for the invention suitthat heating of the metal-bearing gases to the decomposition point takes place at or closely adjacent the surface of the insulating material and also by this preheating means to avoid thermal shock in the material. The preheating temperature may generally be about Va of the final temperature and a short period of stabilization is desirable between the heatings. Accordingly, I also prefer to vaporize the metal-bearing compounds at as low a temperature as is consistent with the required concentration of the metal-bearing gases in the plating chamber. Such practice insures of good bonding between the insulating material and the deposit of metal.

The invention will be more fully understood by reference to the following description and to the accompanying drawing wherein the single figure sets forth a schematic representation of the apparatus for they practice of the invention.

Referring to the drawing, there is shown generally at A a constant temperature system for the supplying of gases at uniform temperature conditions to the remainder of the system; there is shown at B a carrier system for the passage of continuous lengths of insulating material through the unit; there is shown generally at C a system of plating chambers connected with the constant temperature 7 system A and the carrier system B; and there is shown at-D a recovery system for the gases exhausted from the plating chamber.

Referring first to the constant temperature system A, there is shown at 1 a cylinder containing carbon dioxide 2 under pressure. The cylinder 1 is equipped with a valve 3 and a gauge 70 for indicating the flow of gases to a line 4 terminating at 5 in a coil which closely surrounds carburetor casing or gas mixing chamber 6 containing granular copper acetylacetonate 7. Tubular coil 5 and carburetor 6 are immersed in oil contained in tank 9 and this assembly is heated by electrical heater 10 provided with a thermostatic control indicated generally by element 11 and conductor 12 which latter is secured to the heater 10 in a known manner.

The tubular coil 5 is connected into the base of the carburetor-casing 6 Whichcasing has an insulated conduit 13- extending-frorn-the top-thereof; Conduit-13: passes into the top of a plating chamber 42'of plating system C. Conduit 13 is also provided with a valve 14 and a by-pass -li'ne' containing- -valves, 15, 16 and pump-117: secondby-pass 1 line -18fprovided' with valve"19f-extends from the-c0nduit '13 tothe bottom of the plating chant ber 44. Line-18 is--also-providedwith valve-'20 and a by-pa'ss line-'containing valves 21, 22 and pump23z Thecarrier system B for the movementjofthe insulating material comprises a chamber-ZS-opens to the air at inlets-32,-33 -and outlet34; Thechamber contains rollers 27, 28, 29Pa11 d- 3l-over which the insulated'm'aterialfifl may pass from reel 24; i

The Gh amb er 2 5 ani its conte'nts are heated'rbyfheaterunit--35, Aficond uitfl36jisconnected"to therightJh'a'nd sideofchamber and contains *roller 38 and iroller .39 1' forward =of which -is positioned. electrical. resistance. heater: elements 37.? The'right 'handiend' of co'nduit "36' is 'jcon-,-. nected to plating chamber 42 thr'oughf'seal 46 and, cha'mi 2O ber '52 is in turn 3 connected to conduit. '71 through; gas tight seal-47 fandthe" right handendiof conduit 71. is connected to chamber'44'by a'similarj' gas tight seal v48. I: The-righthand end of chamber .44 is connected through.- seal 49'to a tubular portion 72 containing, gas tight'seals;fl 50- and51." Closelyadjacent'the righthand, end of im ue lar member 72 istake=up-"reel' 40 driven. by1a variable speed motor llr' 'e ycarriei system may be provided with pairs on] roller-s64, 65, 66, 67 and 6816?," each pairrbeing adapted! foFaclos'e', engagement thereof with insulating mate rial '30:":

Plati'ngsystemC comprises the plating chambe rsfil 44:; The inlet end ;0f chamber,42, as already noted, is.

connectedtoconduit'113jof system A The outlet end of chamber 42 is provided with a conduit 52 having a valve 43r'therein; The lowerportion of chamber'44 as has: been' noted he'r'einbefore, is connected with conduit v18 andtheupperlend ofrthis chamber is provided with a conduit53 havingja valve 45; conduit 53'extends down andq connects with line. 52 lbelow' the valve 43.

The'recovery system D comprises a tank 56 containing co'olingyvaterSSjwhich passes' in through inlet 57 and out throughfoutl'et 58.1 Atrap 54 .hastone end thereof connectedjtotline 52,: while the'other end-of the trap-is cone-: nected'throughl valves 59 and'60 to the atmosphere.

The exhaust line 173 .from.; the trap 54v is also provided with a by -pass hayinglavalves 161,- 62 a11d, a vacuum p mps 6 :1, 7

Considerin'gzfithe ,operationt of r the apparatus generally- '50 insulating 'glass fabrioas .at 30arna-y be; passed through: reel 24'through the preheating chamber 25 ,into -.condnittt 36 where, ,further heating of the materialgtakemplace. The njati'il'fis thendrawn-through to the plating :cham-Q. bers whereiihe metallic; depositiontakes place and :thenI-L pastlithe.sea1s 46 147, 48, 49: and the outer seals 50,51,11 anclth'e'rpla'tedrnaterial wound up on the-roller 340.

'Morespe'cific'ally. it is generally desirable to initiate ttheii operation'by passingc a tail through-the carrier systenm, B and .fthen pulling the glass fabric through with said 3 0 tail. Siich' procedure eliminates waste of expensive :ima teri'al. t

The fabric 30 entering chamber 25 is heated .bywarm air, rising from, the vicinity. of inlets 32, .33' and heater 351to outlet'34r The preheated fabric. thenepassesl into 05 conduit 36 and is supportedin its passage therethrough bytlie pair .of rolls 38, 39 between :Which rollsithe -fabri'cf passes; Prior; to entering between the rolls. 38, 39' the it fabric isadditionally heatedby heater 37 to atempera-ature of {about 600 F. Meanwhile avalve 30f cylinder l 7 hasbeen released to pass a given quantity of gasuthrough lineal and,coi l '5. The temperature of the oill8 has been brought .to the desired; carburetor temperature of 375 FL through means of heaterlQ-and aceordingly'ii. carbon diqrride gas hefore-entering the carburetorgfi will 75 4,3 be heated. Since material 7 of carburetor 6 also lies in the heated oil; vapor-pressures"of copper'acetyl'a'cetonate will have beendeveloped in the chamber and the entering heated carbon dioxide will sweep these gases into con-t duit 13. r t

In the embodiment of-theinvention being described valves-14 in line 13, and valve-20in line 18' may be considered to be closed',""all others'being 'opened. Under this condition plating gas will pass from line 13 through, yalve'15, pump, 17fand valve 16-to plating chamber 42, while another portion of the gas will pass throughiliiic 18, valve 21, pump 23 and valve 22 to the bottom of chamber .44. The. 4 gases entering ithe 'top'fchamberi: 4213 wilLbe forced downwardlyibythe action of pump 17' nd will contact glass fabric 30 heated to temperature-chap proximately 600 Fr The metal-bearing vapors when they contact the heated fabric will decompose depositing metal on the upper-surface 'thereof,"very' little decomposition"takingipiace upon, the lower surface. Meanwhile the vapors from' line '18' entering plating chamber 44 at the base Willcontactthe lower surface of material 36 depo'sitingiyapors thereon.

The gases of decomposition. from both chamber-42am chamber 44 will pass throughfvalves 43 and 45,1 respectively, and to the recovery apparatus 54 in tank 56,where"- in..any;metal-rb'earing vapors not decomposed will bev settled out while the more volatileigases suchiascarbon dioxide land carbonmonoxide will pass on r to. line =73 through 'open'valves 59, to the atmosphere. Valves .61 and 62 are inthis instance maintained-closed and vacuum pump63'i's not operated. f

Meanwhile the-heated glass fabric containing the metal coats will pass through the seals '50, '51Tandbe' wound/ upion reel 40 driven by motor 41. ln this'f passage the material may be air cooled ormaybe wounduppin the heated condition as desired. 7 V j i It willbe' clear that Where it is not desired to apply. platinggases to both :sides of the insulatedafabric -work* piece, the: upper side may be readily coatedby shutting off valve l9,thus directing all the plating vapors throughf chamber 42; Similarly, the under side of'the-m'aterial: may be coated-by simply closing valves 14, 15:0fline-13 and opening valves 19, 20, or where desired valves-.19, 21, 22.

It will also be noted that the apparatus may be operatedxunder vacuum conditions by closing valve 59 and:

opening valve 61 to -.vacuum pump 63. In this condition":

valves15, 16 -21, 22 should also'be closed:

F urther' examples of operating conditions particularly suitable for the practice of the invention are set forth in the following Examples II and III.

7 EXAMPLE II" lvletal-b'earing' compounm; Chromium carbonyl. Non-conductive material Fiber-glass wool. Carrier gas; Carbon dioxide;

Flowrateof the carriergas 3 liters perminute;

Plating pressure; Substantially atmospheric. Carburetor temperatu're 180 F. 1

EXAM PLE .III

Metal-'bearingcornpouni Nickel carbonyl.

' Noneconductivematerial Asbestosfabric. 7 Carrier gas' Carbon dioxide. Flow'rate 'of the carrier gas 7'lite'rs per minute; Plating pressure Substantially. atmospheric. Carburetor'temperature F.

The preferable temperature. rauge' for the non-coudu'ctivemat'en'al is .between'about 550-700 F. but may be 7 varied to meet:specificip'lating gas conditions; 1

Thefiowrrate :of the carrier gas entering the 'jheating 1 g coils 5. preferably ovaries between-about 1 to 'l0ilitrspe'r minute and the actual volume contacting the insulating ma1erial. will be "higher due to themetal-b'earin'g vapor pick up and heating. Normally the fiow rate is not critical and with given apparatus the stated rate of liters may be exceeded. However the velocity attained by the gas mixture moving against the insulating material should not be such that the material will be cooled by the gases. Should this occur inferior plating and even oxide formation may occur.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions accordingly, it is desired to comprehend such modifications within this invention as fall within the scope of the appended claims.

I claim:

1. Apparatus for gas plating continuous lengths of electrically non-conductive material by subjecting the same to a heat-decomposable gaseous metal bearing compound and heat decomposing the same while in contact with said material, said apparatus comprising an elongated enclosure, said enclosure comprising a heating chamber for preheating said material and a plurality of chambers arranged in cooperating relationship therewith and through which the preheated material is moved from said preheating chamber, means arranged in spaced relationship throughout said elongated enclosure for supporting and go ing said material as drawn from a source and after plating rolled up on a storage reel, means for heating said preheating chamber to heat said material to a temperature above that at which the heat-decomposable gaseous metal compound decomposes, said plating chambers comprising a first plating chamber connected to said heating chamber and a second plating chamber spaced from and connected by a gas impervious enclosure to said first chamber, said plating chambers forming elements of said enclosure and disposed transversely thereof, means for supplying thermally decomposable metal bearing plating gas at a constant temperature, means for admixing an inert carrier gas with said plating gas, means for introducing the resultant mixture of plating gas and carrier gas into said first plating chamber and flowing the same in contact with the upper surface of the material, and introducing said plating gas into the second plating chamber in opposite direction to that of said first plating chamber whereby to plate the opposite surface of said material, said plurality of plating chambers being arranged to plate one side in one chamber and then the opposite side of said material in the other chamber as the same is moved therethrough.

2. In apparatus for gas plating continuous lengths of electrically non-conductive material by subjecting the same to heat decomposable gaseous metal bearing compound and heat decomposing the same while in contact with said. material, said apparatus comprising an elongated enclosure through which said material is moved, said enclosure comprising a heating chamber for pre- 'heating said material and a plurality of chambers arranged in cooperating relationship therewith and through which the preheated material is moved from said preheating chamber, means for supplying said heat decom gaseous metal bearing compound at uniform temperature, means for heating said preheating chamber to heat said material during the passage of continuous lengths of insulating material through said enclosure, said ality of chambers comprising first and second plating nbers spaced longitudinally of said enclosure and through which said material is moved, means for conveying the material to be plated from a storage source through said enclosure and plating chambers, said plating chambers having inlet and outlet openings for thetintroduction of said heat decomposable gaseous metal bcar-' ing compound which is heat decomposed in contact with said material, said inlet openings being arranged to introduce plating gas into said first chamber on one side of said material and into said second chamber on the opposite side of said material, whereby the same is gas plated with metal first on one side and then on the opposite side as said material is moved through the enclosure and Wound up on a storage reel, means comprising condenser which is connected to the outlet of each of said plating chambers for recovering waste gases and metal plating gas discharged from said plating chamber, and means comprising a vacuum pump for maintaining sub-atmospheric pressure conditions in said plating chambers, said plurality of plating chambers being thus arranged to plate one side in one chamber and then the opposite side of said material in the other chamber as the same is moved therethrough.

References Cited in the file of'this patent UNITED STATES PATENTS 2,324,787 Lundgren July 20, 1943 2,332,309 Drummond Oct. 19, 1943 2,478,817 Gaiser Aug. 9, 1949 2,587,036 Germer et a1. Feb. 26, 1952 2,656,284 Toulmin Oct. 20, 1953 2,671,739 Lander Mar. 9, 1954 

1. APPARATUS FOR GAS PLATING CONTINUOUS LINGTHS OF ELECTRICALLY NON-CONDUCTIVE MATERIAL BY SUBJECTING THE SAME TO A HEAT-DECOMPOSABLES GASEOUS METAL BEARING COMPOUND AND HEAT DESCOMPOSING THE SAME WHILE IN CONTACT WITH SAID MATERIAL, SAID APPARATUS COMPFISING AN ELONGATED ENCLOSURE, SAID ENCLOSURE COMPRISING AN ELONGATED ENPREHEATING SAID MATERIAL AND A PLURALITY OF CHAMBER ARRANGED IN COOPESRATING RELATIONSHIP THEREWITH AND THROUGH WHICH THE PREHEATED MATERIAL IS MOVED FROM SAID PREHEATING CHAMBER, MEANS ARRANGED IN SPACED RELATIONSHIP THROUGHOUT SAID ELONGATED ENCLOSURE FOR SUPPORTING AND GUIDING SAID MATERIAL AS DRAWN FROM A SOURCE AND AFTER PLATING ROOLED UP ON A STORAGE REEL, MEANS FOR HEATING SAID PREHEATING CHAMBER TO HEAT SAID MATERIAL TO A TEMPERATURE ABOVE THAT AT WHICH THE HEAT-DECOMPOSABLE GASEOUS METAL SCOMPOUND DECOMPOSES, SAID PLATING CHAMBERS COMPRISING A FIRST PLATING SCHAMBER CONNECTED TO SAID HEATING CHAMBER AND A SECOND PLATING CHAMBER SPACED FROM AND CONNECTED BY A GAS IMPERVIOUS ENSCLOSURE TO SAID 